Optical isolation enabled by two time-modulated point perturbations in a ring resonator.

Area of Science:

• Photonics and Optical Engineering
• Integrated Optics
• Non-reciprocal Devices

Background:

• Optical isolators are crucial for preventing back reflections in photonic integrated circuits.
• Existing optical isolators often suffer from complex fabrication or limited performance.
• Silicon photonics offers a scalable platform for integrated optical devices.

Purpose of the Study:

• To demonstrate non-reciprocity in a silicon optical ring resonator.
• To design and analyze a novel optical isolator based on time-modulated perturbations.
• To achieve high isolation with low insertion loss in a simplified structure.

Main Methods:

• Utilizing Temporal Coupled Mode Theory (TCMT) for analyzing the time-modulated ring resonator.
• Introducing two small, time-modulated perturbations into a silicon optical ring.
• Side-coupling the perturbed ring resonator to waveguides to form an isolator.
• Validating results with an in-house full-wave solver.

Main Results:

• Achieved 21 dB isolation.
• Obtained -0.25 dB insertion loss at telecommunication wavelengths.
• Identified optimal modulation parameters (frequency, amplitude, perturbation points) using TCMT.
• Demonstrated a simpler implementation compared to existing ring-based isolators.

Conclusions:

• The proposed method effectively creates non-reciprocity in silicon optical ring resonators.
• The designed optical isolator offers a practical and efficient solution for integrated photonics.
• The simplified structure with point perturbations is advantageous for fabrication and scalability.